Close Kin Research Articles

Jaw anatomy of Vegavis iaai (Clarke et al., 2005) from the Late Cretaceous Antarctica, and its phylogenetic implications

Vegavis iaai is without any doubt the most complete and well-known Mesozoic bird from Antarctica. In spite of being known by several specimens, its highly specialized postcranial anatomy has obscured the recognition of its phylogenetic affinities. Skull material from Vegavis is scarce, and the lower jaw is known by a relatively well-preserved articular region of a partially articulated specimen (MACN-PV 19.748). The aim of the present contribution is to describe this articular region and to analyze its potential phylogenetic information. The articular region of Vegavis shows a unique combination of characters that separates it from most Mesozoic lineages. On the contrary, its anatomy is congruent with that of neornithine birds, and particularly from the neoavian clade Aequorlitornithes. Detailed comparisons led to the recognition of several shared features, including a well-developed transverse crest posterior to the articular cotyles, that bears a well-developed lateral tubercle; a short and ventrally deflected retroarticular process; a dorsally exposed posterior fossa; tree cotyles for jaw articulation, with a well-developed caudal cotyle fused to the medial cotyle; and lateral crest anteriorly projected with respect to the lateral cotyle. The three-cotyle articulation of the jaw of Vegavis invited us to review skull anatomy of its close kin Polarornis. A review of the bones of Polarornis indicates that the element previously identified as a quadrate is an uncertain bone, and thus, skull-jaw articulation of this taxon remains unknown. In contrast with previous contributions, we were not able to find diagnostic features of the Galloanserae clade on Vegavis jaw. The neoavian-like jaw of Vegavis contrasts with the anseriform signature of its postcranium, suggesting that this bird held some kind of morphological mosaicism on its skeleton.

Cryptic kin discrimination during communal lactation in mice favours cooperation between relatives

Breeding females can cooperate by rearing their offspring communally, sharing synergistic benefits of offspring care but risking exploitation by partners. In lactating mammals, communal rearing occurs mostly among close relatives. Inclusive fitness theory predicts enhanced cooperation between related partners and greater willingness to compensate for any partner under-investment, while females are less likely to bias investment towards own offspring. We use a dual isotopic tracer approach to track individual milk allocation when familiar pairs of sisters or unrelated house mice reared offspring communally. Closely related pairs show lower energy demand and pups experience better access to non-maternal milk. Lactational investment is more skewed between sister partners but females pay greater energetic costs per own offspring reared with an unrelated partner. The choice of close kin as cooperative partners is strongly favoured by these direct as well as indirect benefits, providing a driver to maintain female kin groups for communal breeding.

SNP Panel and Genomic Sex Identification in Atlantic Halibut (Hippoglossus hippoglossus).

The ability to identify sex is necessary in population biology for a proper understanding of the dynamics of a population. In Atlantic halibut, phenotypic sex identification is not possible due to the lack of significant external morphological differences. We developed an Illumina SNP panel for Atlantic halibut with 4000 SNPs spread evenly throughout the genome with a minor allele frequency MAF ≥ 0.4, except for N = 249 SNPs located in a sex-determining region on chromosome 12, N = 176 of these SNPs were selected to genetically identify male and female individuals using a DAPC analysis. The genomic identification of sex allows for non-lethal sex determination and validation of sex identification in the field. The SNP panel is a new genomic resource for Atlantic halibut that will make it possible to generate the genotypic data for the large number of individuals needed to estimate population abundance using genomics and the Close Kin Mark Recapture (CKMR) approach, an emerging component of fisheries management and stock monitoring.

Vocal recognition of former group members, but not unknown kin, in the cooperatively breeding southern pied babbler

Studies of vocal kin recognition in avian species have typically tested responses to vocal signals based upon either familiarity (recognition via ‘learned associations’) or relatedness (recognition of genetic kin) but have rarely simultaneously tested for the effects of both. Here we examined vocal kin recognition in the cooperatively breeding southern pied babbler, Turdoides bicolor, using vocalizations from familiar kin, unfamiliar kin, familiar nonkin and unfamiliar nonkin in a playback experiment. We found limited support for recognition based upon familiarity: individuals appeared to be recognized from a period of prior association and associative learning. Focal birds (dominant females) discriminated familiar birds from unfamiliar birds, but discrimination was evident in only one of three behavioural response measures. Focal birds did not discriminate familiar kin from familiar nonkin, nor did they discriminate unfamiliar kin from unfamiliar nonkin, indicating no support for vocal recognition based on relatedness. The context of the experiment also affected discrimination, with focal birds reacting more strongly to calls from females (potential rivals) than to calls from males. Because familiarity in this species arises from the association of individuals in groups, and most groups comprise close kin, familiarity with group members offers a close proxy for kin recognition. While kin recognition systems based upon familiarity do not allow the identification of unfamiliar kin, the benefits of such recognition may be negligible in cooperatively breeding species that live in kin-based groups.

Expanding the ethnographic toolkit: Using medical documents to include kinless older adults living with dementia in qualitative research

Ethnographic research with cognitively impaired older adults can be challenging, in part because cognitive impairment raises questions about the ability to provide informed consent. Relying on proxy consent is a commonly used strategy, but often excludes people with dementia who lack close kin (de Medeiros, Girling, & Berlinger, 2022). In this paper, we describe how we have analyzed existing research data from a well-established and ongoing prospective cohort study, the Adult Changes in Thought Study, along with unstructured text from the medical records of participants who had no living spouse or adult children when they developed dementia, as a way of studying the circumstances, life trajectories, caregiving resources, and care needs of this vulnerable and difficult-to-research group. In this article, we detail this methodology, exploring what can and cannot be gleaned from it, what the ethical implications may be, and how and whether this type of research can be considered ethnographic. In conclusion, we argue that collaborative interdisciplinary research using existing, longitudinal research data and text from medical records deserves to be considered as a potentially useful addition to the ethnographic toolkit. We anticipate that this is a methodology that could be applied more broadly, and paired with more traditional ethnographic methods, might be one way to make research with this population more inclusive.

Drivers and consequences of female reproductive competition in an egalitarian, sexually monomorphic primate

Even after the 150th anniversary of sexual selection theory, the drivers and mechanisms of female sexual selection remain poorly studied. To understand demographic circumstances favoring female-female competition, trade-offs with kin selection and interactions with male reproductive strategies, we investigated female evictions in redfronted lemurs (Eulemur rufifrons). Based on 24 years of demographic data of known individuals, we show that female redfronted lemurs target close female kin for forcible, permanent, and presumably lethal eviction, even though groups contain multiple unrelated males whose voluntary emigration actually mitigated the probability of future female evictions. Female eviction and male emigration were predicted by group size, but male emigration was primarily driven by a proportional increase of male rivals. Female evictions were more likely than male emigrations when there were more juvenile females in a group, but the identity of evicted females was not predicted by any intrinsic traits. While birth rates were reduced by the number of juvenile females, they were higher when there were more adult females in a group and in years with more rainfall. Early infant survival was reduced with increasing numbers of juvenile females, but variation in female lifetime reproductive success was not related to any of the predictors examined here. Thus, there seems to be a limit on female group size in this lemur species. More generally, our study demonstrates a balanced interplay between female reproductive competition, competition over group membership between both sexes, and kin selection, contributing new insights into the causes and consequences of female competition in animal societies.Significance statementThe evolutionary causes of female competition in vertebrate societies remain poorly known. Evictions represent an extreme form of female competition because even close kin are evicted when same-sized unrelated males are theoretically also available as victims. We studied drivers and consequences of evictions in redfronted lemurs (Eulemur rufifrons) using 24 years of demographic data from multiple groups. We show that while voluntary male emigration mitigates the probability of future female evictions, females nonetheless appear to accept the fitness costs of evicting female kin. While group size seems to be the main driver of departures by either sex, the number of juvenile females present in groups is the key variable triggering eviction events as well as physiological responses that could be interpreted as female reproductive restraint. Our study therefore revealed that competition does trump cooperation under some circumstances in the intricate interplay between sexual selection and kin selection on females.

Witness for resolution: post-conflict quadratic affiliation in semi-free ranging pigs.

In social mammals, post-conflict resolution can involve the reunion of former opponents (reconciliation), spontaneous/solicited post-conflict affiliation of a third party with either opponent (triadic contacts), and affiliation between other individuals (hereafter bystanders; quadratic contacts). Quadratic contacts-possibly informing complex cognitive abilities-have been neglected in post-conflict studies. We investigated quadratic affiliation in semi-free ranging pigs Sus scrofa, at the ethical farm Parva-Domus (Cavagnolo, Italy). Kinship was known. We collected behavioral data on adult pigs (n = 104) via video recordings (43 h) followed by video analyses. Affiliative and anxiety behaviors between bystanders were collected under post-conflict (PC; following a conflict between non-bystanders) and matched-control (MC; no conflict) conditions. Quadratic affiliation was present in pigs, as bystanders affiliated more in PC than MC, and such affiliation was followed by a decrease in the anxiety behaviors of both the interacting bystanders. Thus, quadratic contacts may be partly aimed at reducing one's own anxiety (intrinsic regulation). Quadratic affiliation was highest between closely related bystanders, which suggests that such affiliation may be most effective when close kin is involved. Quadratic affiliation was lowest after reconciliation and spontaneous triadic contacts. This suggests that direct peacemaking between opponents and spontaneous triadic contacts with close kin may most likely replace quadratic affiliation. Hence, pigs can be influenced by the negative events that affect other pigs-but not themselves-and their response may be modulated by social factors. Such non-random quadratic affiliation may point toward the presence of elements of social appraisal abilities in pigs.

Cooperation and partner choice among Agta hunter-gatherer children: An evolutionary developmental perspective.

Examining development is essential for a full understanding of behaviour, including how individuals acquire traits and how adaptive evolutionary forces shape these processes. The present study explores the development of cooperative behaviour among the Agta, a Filipino hunter-gatherer population. A simple resource allocation game assessing both levels of cooperation (how much children shared) and patterns of partner choice (who they shared with) was played with 179 children between the ages of 3 and 18. Children were given five resources (candies) and for each was asked whether to keep it for themselves or share with someone else, and if so, who this was. Between-camp variation in children's cooperative behaviour was substantial, and the only strong predictor of children's cooperation was the average level of cooperation among adults in camp; that is, children were more cooperative in camps where adults were more cooperative. Neither age, sex, relatedness or parental levels of cooperation were strongly associated with the amount children shared. Children preferentially shared with close kin (especially siblings), although older children increasingly shared with less-related individuals. Findings are discussed in terms of their implications for understanding cross-cultural patterns of children's cooperation, and broader links with human cooperative childcare and life history evolution.

Moral Economies of Life and Death: Agricultural Improvement, Imperialism, and Chemical Kinships with Reactive Nitrogen

What does it mean to think of chemicals as kin? Building on the concepts of chemical kinships and pollution as colonialism, I use a feminist storytelling methodology grounded in relational ontology to explore my kinship relationships with reactive nitrogen, and the way it both hurts me and gives me life. Agriculture and organic chemistry are close kin to imperialism, capitalism, and environmental destruction, and, as a white British woman, I argue these are also my own more-than-human family: my close kin. To take the call to kinship seriously, I argue for approaching kinship personally, and accepting clear positionality in relation: exploring my relation to how these kin both abuse and support me, our ancestral entanglement, and my own complicity and responsibility in enabling their abuse.

A clinical study on the outcomes of tracheostomy in a tertiary care center: a prospective observational study

Background: Tracheostomy is most commonly performed in patients who have difficulty in weaning off a ventilator. This surgical procedure is associated with complications. The present study was aimed to evaluate the outcomes of tracheostomy with primary and secondary objectives. Methods: This study was done in department of ENT, KIMS Health, Trivandrum, Kerala. Based on the inclusion and exclusion criteria 81 patients were included in the study. Study procedure was explained and informed consent was obtained from close relatives or kin of patients. Demographic, clinical and complication data was collected from the patients and analysed with Statistical Package for Social Sciences (20.0 version) software. Correlation was done between complications and period of decanulation. Results: The study was done in 81 patients under gone tracheostomy. Maximum number of patients had age between 61-80 years. Males were more number than females. Portex type of tube used in maximum patients. 70 patients underwent elective and 11 underwent emergency tracheostomy. 74 patients underwent surgery in operation theatre and 5 in an ICU. Prolonged ventilation is the major indication for tracheostomy. Out of 81 patients 55 did not show any complications. 9 patients developed granulations. Significant correlation was observed between complications with period of decanulation. Conclusions: Postoperative care, regular follow up and proper nursing home care is essential for the patients who require prolonged tracheostomy and also to prevent complications with speedy recovery.

A hazai pálya előnye


 The paper deals with the effects of the structure and the working of the egocentric network to the immobile status of rural youth. The research was made in 2018 among 19-25-year-old youth living in villages with not more than 2500 inhabitants. More, than a hundred (104) structured interview was made: 53 youth and 51 parents. Firstly, the study shows the network size and composition of the examined population, then the influence of the revealed functions of the egocentric network of the youth to their immobility. Based on the data the egocentric network of the youth mainly consist of strong ties: close kin and other relatives. From the weak ties the most frequent contacts belong to the education institutions as primary or grammar school, university. The local schools have a great role in the forming of the friendships. The local working place contacts, neighbours and acquaintanceships are not general actors of the egocentric networks of the youth. 

COVID-19 precautionary behaviors and vaccine acceptance among older individuals: The role of close kin

The family plays a central role in shaping health behaviors of its members through social control and support mechanisms. We investigate whether and to what extent close kin (i.e., partner and children) matter for older people in taking on precautionary behaviors (e.g., wearing a mask) and vaccination during the COVID-19 pandemic in Europe. Drawing on data from the Survey of Health, Ageing and Retirement in Europe (SHARE), we combine its Corona Surveys (June to September 2020 and June to August 2021) with pre-COVID information (October 2019 to March 2020). We find that having close kin (especially a partner) is associated with a higher probability of both adopting precautionary behaviors and accepting a COVID-19 vaccine. Results are robust to controlling for other potential drivers of precautionary behaviors and vaccine acceptance and to accounting for coresidence with kin. Our findings suggest that policymakers and practitioners may differently address kinless individuals when promoting public policy measures.

Number of Close Kin but Not Gendered Fitness Interests Shapes Sex Role Attitudes

Number of Close Kin but Not Gendered Fitness Interests Shapes Sex Role Attitudes

Agta hunter-gatherer oral microbiomes are shaped by contact network structure.

Here we investigate the effects of extensive sociality and mobility on the oral microbiome of 138 Agta hunter-gatherers from the Philippines. Our comparisons of microbiome composition showed that the Agta are more similar to Central African BaYaka hunter-gatherers than to neighbouring farmers. We also defined the Agta social microbiome as a set of 137 oral bacteria (only 7% of 1980 amplicon sequence variants) significantly influenced by social contact (quantified through wireless sensors of short-range interactions). We show that large interaction networks including strong links between close kin, spouses and even unrelated friends can significantly predict bacterial transmission networks across Agta camps. Finally, we show that more central individuals to social networks are also bacterial supersharers. We conclude that hunter-gatherer social microbiomes are predominantly pathogenic and were shaped by evolutionary tradeoffs between extensive sociality and disease spread.

Kinship analysis reveals low dispersal in a hog deer (Axis porcinus) population in Wilsons Promontory National Park, Australia

Context A wild population of non-native hog deer has established in the Gippsland region of Victoria, Australia, and there is particular concern about its impact on native vegetation in Wilsons Promontory National Park (WPNP). Since 2015, there has been annual culling of hog deer at WPNP to reduce deer abundances and impacts. Aims The aims of this study were to use a kinship approach based on genotyping to assess contemporary dispersal of hog deer across WPNP, by identifying close kin, to determine whether dispersal of deer into culled sites from unculled sites may affect the long-term success of management there. Differences in the dispersal of male and female hog deer were also investigated. Methods In total, 91 hog deer tissue samples were collected across WPNP and surrounding sites. Single nucleotide polymorphism (SNP) markers were sequenced, and a final dataset comprising 8275 SNPs was used for analysis. First-order, second-order, and intermediate relative pairs were identified, and the geographic distance between these pairs was assessed to determine inter-pair distances to infer dispersal. Spatial autocorrelation between male and female samples was evaluated to measure the effects of sex-biased dispersal. Key results Only seven second-order relative pairs were found across different sites, with a 30 km distance between the furthest pair observed. However, most inter-pair distances across sites were ~5–10 km. Analyses of sex-biased dispersal showed that movement by deer was not strongly influenced by one sex. Conclusions Although hog deer in WPNP are genetically similar, most relatives that were sampled were not widely dispersed. This suggests that there is limited dispersal of hog deer across this park. Implications Recolonisation of hog deer at culled sites via dispersal is likely to be infrequent in WPNP. Kinship analysis provides an effective method of assessing contemporary dispersal and could be applied to other species to assess fine-scale movement across landscapes.

Making kinship away from home: chronic disease and the Pakistani diaspora in the US

The article considers several generations of Pakistani immigrants from Karachi to various cities in the United States such as Chicago and New York and explores how chronic diseases are shaped by the reverberations of conflict in kin relations in the US and Pakistan. Instead of examining the experience of chronic illness in isolation, the article considers how webs of evolving relations, tensions, competition, and conflicts among distant and close kin are experienced by the vulnerable and those who try to care for them. These conflicts are shaped by the experience of absence and also in the lives of intimate kin, and often appear in violent form. In navigating these relations, caregivers of those with illnesses develop strategies to maintain communications with wider kinship networks while also shielding the sick from the ramifications of ongoing disputes.

Urban population structure and dispersal of an Australian mosquito (Aedes notoscriptus) involved in disease transmission

Dispersal is a critical parameter for successful pest control measures as it determines the rate of movement across target control areas and influences the risk of human exposure. We used a fine-scale spatial population genomic approach to investigate the dispersal ecology and population structure of Aedes notoscriptus, an important disease transmitting mosquito at the Mornington Peninsula, Australia. We sampled and reared Ae. notoscriptus eggs at two time points from 170 traps up to 5 km apart and generated genomic data from 240 individuals. We also produced a draft genome assembly from a laboratory colony established from mosquitoes sampled near the study area. We found low genetic structure (Fst) and high coancestry throughout the study region. Using genetic data to identify close kin dyads, we found that mosquitoes had moved distances of >1 km within a generation, which is further than previously recorded. A spatial autocorrelation analysis of genetic distances indicated genetic similarity at >1 km separation, a tenfold higher distance than for a comparable population of Ae. aegypti, from Cairns, Australia. These findings point to high mobility of Ae. notoscriptus, highlighting challenges of localised intervention strategies. Further sampling within the same area 6 and 12 months after initial sampling showed that egg-counts were relatively consistent across time, and that spatial variation in egg-counts covaried with spatial variation in Wright’s neighbourhood size (NS). As NS increases linearly with population density, egg-counts may be useful for estimating relative density in Ae. notoscriptus. The results highlight the importance of acquiring species-specific data when planning control measures.

Kinship and similarity drive coordination of breeding-group choice in male spotted hyenas.

When and where animals reproduce influences the social, demographic and genetic properties of the groups and populations they live in. We examined the extent to which male spotted hyenas (Crocuta crocuta) coordinate their breeding-group choice. We tested whether their propensity to settle in the same group is shaped by passive processes driven by similarities in their socio-ecological background and genotype or by an adaptive process driven by kin selection. We compared the choices of 148 pairs of same-cohort males that varied in similarity and kinship. We found strong support for both processes. Coordination was highest (70% of pairs) for littermates, who share most cumulative similarity, lower (36%) among peers born in the same group to different mothers, and lowest (7%) among strangers originating from different groups and mothers. Consistent with the kin selection hypothesis, the propensity to choose the same group was density dependent for full siblings and close kin, but not distant kin. Coordination increased as the number of breeding females and male competitors in social groups increased, i.e. when costs of kin competition over mates decreased and benefits of kin cooperation increased. Our results contrast with the traditional view that breeding-group choice and dispersal are predominantly solitary processes.

Fitness consequences of cousin marriage: a life-history assessment in two populations.

Cousin marriage, a spousal union between close kin, occurs at high frequencies in many parts of the world. The rates of cousin marriage in humans are concordant with empirical studies that challenge the traditionally held view that reproduction with kin is generally avoided in animals. Similarly, some theoretical models in animal behaviour show that inbreeding avoidance is more constrained than previously thought. Such studies highlight the importance of quantifying the costs and benefits of reproduction among close kin over the whole life-course. Here, we use genealogical data from two human populations with high frequencies of cousin marriage (the Dogon from Mali, and the Ancien Régime nobility from Europe) to estimate these potential costs and benefits. We compare age-specific fertility and survival curves, as well as the projected growth rates, of subpopulations of each marriage type. Fitness costs of cousin marriage are present in terms of reduced child survival (in both populations), while benefits exist as increased fertility for men (in the Dogon) and for women (in the Ancien Régime nobility). We also find some differences in the projected growth rates of lineages as a function of marriage type. Finally, we discuss the trade-offs that might shape marriage decisions in different ecological conditions.

Starting from scratch in a patrilocal society: how women build networks after marriage in rural Bangladesh.

Humans rely on both kin and non-kin social ties for a wide range of support. In patrilocal societies that practice village exogamy, women can face the challenge of building new supportive networks when they move to their husband's village and leave many genetic kin behind. In this paper, we track how women from 10 diverse communities in rural Bangladesh build supportive networks after migrating to their husband's village, comparing their trajectories with women who remained in their childhood village (Bengali: n = 317, Santal: n = 36, Hajong: n = 39, Mandi: n = 36). Women who migrated for marriage started with almost no adult close kin (mean 0.1) compared to women who remained in their childhood village (mean 2.4). However, immigrants compensated for the lack of genetic kin by a combination of close affinal kin and close friends. By their late 20s, immigrants reported substantially more non-kin friends than did non-immigrants (mean 1.4 versus 1.1) and a comparable number of supportive partners in several domains. These findings raise questions about the functions and quality of these different social ties and how different composition of supportive networks may provide different opportunities for women in these settings. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.